Please refer to FIG. 1, a conventional filter test strip includes a filter cotton holding layer 1, a cotton bonding layer 2 and a test element 7. The filter cotton holding layer 1 and cotton bonding layer 2 are bonded by an adhesive 3 between them. The filter cotton holding layer 1 has a filter cotton 4 to filter blood 5 and remove blood cells to separate the blood cells and plasma, and allow only the plasma to pass through filter cotton to be captured. The plasma enters the test element 7 to be tested to get physiological data such as cholesterol, uric acid and the like.
In the aforesaid conventional structure, the filter cotton 4 is made of porous material to filter the blood cells of the blood 5 and separate the blood cells and plasma. However, the porous material tends to form uneven surfaces and gaps at the borders. When the filter cotton 4 is held in the filter cotton holding layer 1 gaps 6 are inevitably formed between the filter cotton 4 and filter cotton holding layer 1 that easily let the and blood cells to percolate through. Moreover, because the adhesive 3, the filter cotton 4 and cotton bonding layer 2 cannot form a tight bonding among them, some of the blood cells in the blood 5 tend to pass through the filter cotton 4 through the gaps 6 and between the filter cotton 4 and cotton bonding layer 2 to blend with the filtered blood 5 containing only the plasma. In other words, in the conventional structure the filter cotton 4 cannot fully filter out the blood cells in the blood 5. It contains residual blood cells during the test that affect test accuracy, thus cannot fully meet use requirements.